Optical apparatus

ABSTRACT

An optical apparatus includes a cam barrel configured to hold an optical member, which is movable back and forth along a first optical axis, on an inner periphery of the cam barrel, a bending member configured to bend a light flux from an object from the first optical axis towards a second optical axis, and a guiding member extending in a direction parallel with the second optical axis and configured to support and hold the bending member to be movable back and forth in the direction parallel with the second optical axis, wherein the guiding member is configured to enter into a notch, which is provided to the cam barrel, when the optical member is stored into a space along the first optical axis into which the bending member has retracted.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a zoom type lens barrel that can changea shooting magnification by moving between a storage position and ashooting position along an optical axis.

2. Description of the Related Art

As a type of an imaging apparatus including a zoom type lens barrel,such as a digital camera, Japanese Patent Application Laid-Open No.2009-122640 discusses an imaging apparatus including a reflectionoptical element, such as a prism, which guides light flux incidentthereto from a plurality of lens units into an image sensor by bendingthe light flux in a direction intersecting with an optical axis toachieve a small size lens barrel. In the zoom lens discussed in theabove-described conventional apparatus, a light flux incident from afirst lens unit is bent in a direction substantially perpendicular to alight-incident optical axis (i.e., in a direction towards the imagesensor) by using a reflection optical element, such as a prism, which isarranged in a rear portion of the first lens unit of the lens barrel.

Even if the size of the first lens unit provided on the lightflux-incident optical axis is large, it is desired by the market toprovide a camera having a thin body by reducing the dimension of thecamera in the direction of the light-incidence optical axis in a lensbarrel retracted state. However, a guide shaft, which guides a member ona second optical axis, may become a bottleneck against the reduction ofthe size of an imaging apparatus body because the guide shaft mayinterfere with a member provided on the first optical axis during thelens barrel storage operation.

SUMMARY OF THE INVENTION

The present invention is directed to an imaging apparatus whosethickness can be further reduced.

According to an aspect of the present invention, an optical apparatusincludes a cam barrel configured to hold an optical member, which ismovable back and forth along a first optical axis, on an inner peripheryof the cam barrel, a bending member configured to bend a light flux froman object from the first optical axis towards a second optical axis, anda guiding member extending in a direction substantially parallel withthe second optical axis and configured to support and hold the bendingmember to be movable back and forth in the direction substantiallyparallel with the second optical axis, wherein the guiding member isconfigured to enter into a notch, which is provided to the cam barrel,when the optical member is stored into a space along the first opticalaxis into which the bending member has retracted.

According to another aspect of the present invention, an opticalapparatus includes a first optical member configured to be movable backand forth along a first optical axis, an advancement guide memberconfigured to regulate a rotation of the first optical member around thefirst optical axis of the first optical member, a bending memberconfigured to bend a light flux from an object from the first opticalaxis towards a second optical axis, and a guiding member extending in adirection substantially parallel with the second optical axis andconfigured to support and hold the bending member to be movable back andforth in the direction substantially parallel with the second opticalaxis, wherein the guiding member is configured to enter into a notch,which is provided to the advancement guide member, when the opticalmember is stored into a space along the first optical axis into whichthe bending member has retracted.

Further features and aspects of the present invention will becomeapparent from the following detailed description of exemplaryembodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate exemplary embodiments, features,and aspects of the invention and, together with the description, serveto describe the principles of the invention.

FIG. 1 is a cross section of main components of a digital camera, whichis an exemplary embodiment of an imaging apparatus of the presentinvention, in which a lens barrel of the digital camera is positioned ata wide-angle end.

FIG. 2 is a front view of main components of the digital cameraillustrated in FIG. 1, when viewed from an object side of a first lensunit.

FIG. 3 is a perspective view illustrating an example mechanism fordriving a third lens unit.

FIG. 4 is a perspective view of a diaphragm-shutter.

FIG. 5 is a perspective exploded perspective view of thediaphragm-shutter.

FIG. 6 is a cross section of the main components of the digital camera,in which a lens barrel of the digital camera is positioned at atelephoto end.

FIG. 7 is a front view of the digital camera illustrating the maincomponents thereof illustrated in FIG. 6, when viewed from the objectside of the first lens unit.

FIG. 8 is a cross section of the main components of the digital cameraviewed when the lens barrel is positioned at a sink position (storageposition).

FIG. 9 is a front view of the digital camera illustrating the maincomponents thereof illustrated in FIG. 8, when viewed from the objectside of the first lens unit.

FIG. 10 is a perspective exploded perspective view of a cam barrel and apart of a mechanism for driving a prism.

FIG. 11 is a plan view illustrating a holding member configured to holda prism, and a part of a prism drive unit.

FIG. 12 is an expansion view of a fixed barrel viewed from an innerperiphery thereof.

FIGS. 13A through 13C illustrate a phase relationship between a prismcarrier and a prism delay gear, and an amount of charge applied to atorsion spring.

FIG. 14 is a perspective view illustrating a partial cross section of acam barrel and a prism drive mechanism.

FIG. 15 illustrates a lens barrel positioned at a sink position (storageposition) from a back surface side thereof.

FIG. 16 is a cross section illustrating the main components of the lensbarrel positioned at the sink position (storage position) sectionedalong a plane perpendicular to an optical axis B.

FIG. 17 is a perspective view of the lens barrel positioned at the sinkposition (storage position) viewed from an object side of the first lensunit included in the camera body in a direction of an optical axis.

FIG. 18 is a perspective view of an imaging apparatus viewed from thedirection of the optical axis of the first lens unit.

FIG. 19 is a partial perspective view of the lens barrel positioned atthe sink position (storage position).

FIG. 20 is a cross section of a camera body sectioned in a directionnormal to the optical axis of the first lens unit in a state in whichthe lens barrel is positioned at the sink position (storage position).

FIG. 21 is a cross section of the imaging apparatus when the lens barrelis positioned at the sink position (storage position).

FIG. 22 is a perspective view of an image sensor of the imagingapparatus viewed from an opposite side of an object along the opticalaxis B and.

FIG. 23 is a perspective view of the image sensor viewed from the objectside along the optical axis B.

FIG. 24 is a perspective deal drawing of an image sensor 8, a sensorplate 200, and an imaging substrate 201, which are to be installed tothe lens barrel.

DESCRIPTION OF THE EMBODIMENTS

Various exemplary embodiments, features, and aspects of the inventionwill be described in detail below with reference to the drawings.

FIG. 1 is a cross section of main components of a digital camera, whichis an exemplary embodiment of an imaging apparatus of the presentinvention, in which a lens barrel of the digital camera is positioned ata wide-angle position. FIG. 2 is a front view of the main components ofthe digital camera illustrated in FIG. 1, when viewed from an objectside of a first lens unit. In the present exemplary embodiment, it issupposed that the lens barrel is a zoom type lens barrel configured tomove between a storage position and a shooting position along an opticalaxis to change a shooting magnification.

Referring to FIGS. 1 and 2, a digital camera according to the presentexemplary embodiment includes a zoom type lens barrel, which isconstituted by a first lens unit 10, a second lens unit 20, a prism 6, afixed barrel 62, a cam barrel 61, and an advancement guide barrel 63. Inaddition, the digital camera according to the present exemplaryembodiment includes a zoom body 64, which is an example of a lens barrelholding frame of the present invention. In the example illustrated inFIG. 2, the first lens unit 10, the second lens unit 20, the fixedbarrel 62, and the advancement guide barrel 63 are not illustrated.

The first lens unit 10 includes a first-unit lens 1, which is held by afirst lens unit barrel 11. The second lens unit 20, which is a firstoptical member of the present invention, includes a second-unit lens 2,which is held by a second-unit lens barrel 21. The first lens unit 10and the second lens unit 20 can move along an optical axis A. Lightfluxes of light incident from the first-unit lens 1 and the second-unitlens 2 are bent by the prism 6 in a direction of the optical axis B,which intersects the optical axis A of the first-unit lens 1 and thesecond-unit lens 2 with an angle of approximately 90°.

As described above, the light flux from an object is bent to be guidedto an image plane of an image sensor 8. Accordingly, the prism 6functions as a light flux bending member. The prism 6 is held by aholding member 60 and can move along the optical axis B. The opticalaxis A corresponds to a first optical axis of the present invention. Theoptical axis B corresponds to a second optical axis of the presentinvention.

A diaphragm-shutter 9, which is configured to control the light amountduring shooting, a third-unit lens 3, a fourth-unit lens 4, a fifth-unitlens 5, and an optical filter 7 are provided along the optical axis Bbetween the prism 6 and the image sensor 8, in order from the prism 6 tothe image sensor 8. The third-unit lens 3, the fourth-unit lens 4, andthe fifth-unit lens 5 each correspond to an optical member of thepresent invention.

The diaphragm-shutter 9 is fixed to a shutter ground plate 92. Thethird-unit lens 3 is held by a third unit-ground plate 31. The thirdunit-ground plate 31 and the shutter ground plate 92, which areintegrated together by using a screw, constitute a third lens unit 30.Changing of magnification is performed by the third lens unit 30 bymoving along the optical axis B. The third lens unit 30 is driven by astepping motor 32.

FIG. 3 is a perspective view illustrating a drive mechanism for thethird lens unit 30, which is an example of a second optical member ofthe present invention. Referring to FIG. 3, a gear 33 is attached to anoutput axis of the stepping motor 32. The gear 33 engages with a gear 34to rotate a screw 35 with increased speed.

A rack 36, which is attached to the third unit-ground plate 31, engagesthe screw 35. In addition, the third unit-ground plate 31 is supportedand held by guide shafts 86 and 87. The guide shafts 86 and 87 are guidemembers provided in parallel to the optical axis B. With theabove-described configuration, the third unit-ground plate 31 can movealong the optical axis B. Furthermore, with the above-describedconfiguration, the rack 36 is subjected to a force in the direction ofthe optical axis B as the screw 35 rotates. Moreover, the third lensunit 30 moves in the direction of the optical axis B together with therack 36.

FIG. 4 is a perspective view of the diaphragm-shutter 9. FIG. 5 is anexploded perspective view of the diaphragm-shutter 9. Referring to FIGS.4 and 5, the diaphragm-shutter 9 includes a shutter ground plate 92, acover 96, and a plurality of blades 94 and 95. The cover 96 is providedat a position close to the third unit-ground plate 31. The plurality ofblades 94 and 95 is provided between the shutter ground plate 92 and thecover 96, and moves to open and close an opening 96 c. The cover 96 andthe shutter ground plate 92 are fixed together by using a screw 87.

A stepping motor 91 is an actuator configured to drive the plurality ofblades 94 and 95 included in the diaphragm-shutter 9 to open and close.A lever 93, which extends in a direction perpendicular to an axis of amotor shaft, is fixed to the motor shaft of the stepping motor 91.Shafts 93 a and 93 b, which protrude from the lever 93 in a direction inwhich the lever 93 extends, are respectively provided on both edges ofthe lever 93.

The shaft 93 a is inserted into an arc-like hole 92 a, a long hole 94 a,and the arc-like hole 96 a. The arc-like hole 92 a is formed on theshutter ground plate 92. The long hole 94 a is formed on the blade 94.The arc-like hole 96 a is formed on the cover 96. The shaft 93 a canmove along the arc-like holes 92 a and 96 a. The shaft 93 b is insertedinto an arc-like hole 92 b, a long hole 95 a, and an arc-like hole 96 b.The arc-like hole 92 b is formed on the shutter ground plate 92. Thelong hole 95 a is formed on the blade 95. The arc-like hole 96 b isformed on the cover 96. The shaft 93 b can move along the shape of thearc-like holes 92 b and 96 b.

When the lever 93 is driven and rotated by the stepping motor 91, theblades 94 and 95 turn in mutually reverse directions. With areciprocating turning operation of the blades 94 and 95, the opening 96c is opened and closed. With the above-described configuration, anaperture stop function for controlling the amount of light duringshooting is implemented by adjusting a clearance between the blades 94and 95 configured to open and close the opening 96 c. In addition, ashutter function is implemented by moving the blades 94 and 95 from astate in which the opening 96 c is open to a state in which the opening96 c is closed.

Returning to FIGS. 1 and 2, the fourth-unit lens 4 is held by a fourthlens unit holder 41. The fourth-unit lens 4 and the fourth lens unitholder 41 constitute a fourth lens unit 40. The fourth lens unit 40 isthe second optical member of the present invention. The fourth lens unit40 is supported and held by the guide shafts 86 and 87, and can movealong the optical axis B. In addition, the fourth lens unit 40 ispressed by a spring (not illustrated) towards the object side. Duringshooting, the fourth lens unit 40 contacts a stopper (not illustrated)and is fixed at a position illustrated in FIGS. 1 and 2.

The fifth-unit lens 5 is held by a fifth lens unit holder 51. Thefifth-unit lens 5 and the fifth lens unit holder 51 constitute a fifthlens unit 50. The fifth lens unit 50 is the second optical member of thepresent invention. The fifth lens unit 50 is supported and held by theguide shafts 86 and 87, and can move along the optical axis B. Changingof the magnification and focusing are performed by causing the fifthlens unit 50 to move along the optical axis B by a force transmittedfrom a screw 42 a, which is driven and rotated by the stepping motor 42.The optical filter 7 functions as a low-pass filter configured to cutlight of a high spatial frequency and as an infrared-ray cut filter.

FIG. 6 is a cross section of the main components of the digital camera,in which the lens barrel is positioned at a telephoto end. FIG. 7 is afront view of the digital camera illustrating the main componentsthereof illustrated in FIG. 6, when viewed from the object side of thefirst lens unit. In the example illustrated in FIG. 7, the first lensunit 10, the second lens unit 20, the fixed barrel 62, and theadvancement guide barrel 63 are not illustrated.

Referring to FIG. 6 and FIG. 7, when the lens barrel is positioned atthe telephoto end, the first lens unit 10 advances towards the objectside along the optical axis A. In addition, the second lens unit 20stops at a position close to the prism 6 after retracting along theoptical axis A. The third lens unit 30, which is driven by the steppingmotor 32, stops at a position close to the prism 6 after moving alongthe optical axis B towards the prism 6.

As illustrated in FIG. 7, the stepping motor 91, which drives the blades94 and 95 of the diaphragm-shutter 9 to open and close, is providedbelow the prism 6 at a position at which the entire stepping motor 91 isoverlapped with the prism 6 and at which the position of the steppingmotor 91 in the direction of the optical axis B matches the position ofthe prism 6. The fourth lens unit 40, which is driven by the steppingmotor 42, stops at a position close to the image sensor 8 after movingtowards the image sensor 8 along the optical axis B.

FIG. 8 is a cross section of the main components of the digital cameraviewed when the lens barrel is positioned at a sink position (storageposition). FIG. 9 is a front view of the digital camera illustrating themain components thereof illustrated in FIG. 8, when viewed along theoptical axis of the first lens unit. FIG. 15 illustrates the lens barrelpositioned at the sink position (storage position) from a back surfaceside thereof. FIG. 16 is a cross section illustrating main components ofthe lens barrel positioned at the sink position (storage position)sectioned along a plane perpendicular to the optical axis B.

Referring to FIGS. 8, 9, and 16, when the lens barrel is positioned atthe sink position, the prism 6, the third lens unit 30, and the fifthlens unit 50 move along the optical axis B towards the image sensor 8 soas not to interfere each other. At this timing, the fourth lens unit 40is pressed by the third lens unit 30 towards the image sensor 8 to becaused to withdraw to the storage position. By executing theabove-described operation, a storage space is formed at a portion to therear of the second lens unit 20 and the first lens unit 10.

The zoom body 64 stores the guide shafts 86 and 87 and the opticalfilter 7. Referring to FIG. 15, the guide shafts 86 and 87 extend to aposition at which the guide shafts 86 and 87 are overlapped with thesecond-unit lens barrel 21, which is provided within the cam barrel 61,in the direction of the optical axis A at one end in the direction ofthe shaft of the guide shafts 86 and 87. At the other end in thedirection of the shaft of the guide shafts 86 and 87, the guide shafts86 and 87 extend to a position at which the guide shafts 86 and 87 holdthe optical filter 7. In addition, the zoom body 64 stores the fixedbarrel 62 on the object side in the direction of the optical axis A.Furthermore, the zoom body 64 stores an array of gears included in thefollowing drive mechanism.

Referring to FIGS. 1, 6, and 8, a dimension X indicates a minimumthickness of a back surface wall of the zoom body 64, which ispositioned to the rear of the prism 6 in the direction of the opticalaxis A (in the opposite direction of the object side) that is not movedtowards the fixed barrel 62, the cam barrel 61, and the image sensor 8.In addition, a dimension Y indicates a dimension from an outer surfaceof the back surface wall of the zoom body 64 (the surface opposite tothe object side) to the holding member 60 of the prism 6. Whencalculated according to the minimum thickness of the zoom body 64 andthe clearance against the holding member 60, the dimension X and thedimension Y has a relationship Y≧X.

In the present exemplary embodiment, a through hole 64 a is formed onthe back surface wall of the zoom body 64. The second lens unit 20 canretract through the through hole 64 a in the direction of the opticalaxis A. Accordingly, the space corresponding to the dimension Y, whichis formed by the through hole 64 a, is included in a retraction spaceformed in a portion to the rear of the first lens unit 10 and the secondlens unit 20 when the holding member 60 of the prism 6 retracts towardsthe image sensor 8. The second lens unit 20 and the first lens unit 10retract along the optical axis A into a storage space including theabove-described spaces to be stored therein.

In addition, as illustrated in FIG. 16, clearance grooves 21 a and 21 b,which is provided to prevent an interference between the second lensunit 20 and the guide shafts 86 and 87 that may otherwise occur when thesecond lens unit 20 retracts along the optical axis A, is formed in aportion corresponding to the guide shafts 86 and 87 of the second-unitlens barrel 21.

Furthermore, in a lens barrel retracted state, the second-unit lens 2 isstored in a position between the guide shafts 86 and 87. In addition, inthe lens barrel retracted state, an R2 surface side of the second-unitlens 2 is provided at a position to the rear of the guide shafts 86 and87 in the direction of the optical axis A by an amount equivalent to adimension Z.

As illustrated in FIG. 9, the stepping motor 91, which drives the blades94 and 95 of the diaphragm-shutter 9 to open and close, is providedbelow the prism 6 at a position at which the entire stepping motor 91 isoverlapped with the prism 6 and at which the position of the steppingmotor 91 in the direction of the optical axis B matches the position ofthe prism 6.

The fixed barrel 62, the cam barrel 61, and the advancement guide barrel63 will be described in detail below. FIG. 19 is a partial perspectiveview of the lens barrel positioned at the sink position (storageposition).

In an inner peripheral portion of the fixed barrel 62, cam grooves 62 a(FIG. 12) are provided at a plurality of positions in a circumferentialdirection with substantially even intervals. More specifically, the camgrooves 62 a are provided along an outer periphery of the cam barrel 61and a cam pin (not illustrated) cam-engages the cam groove 62 a. A gear61 a, which engages a drive gear 68 (the drive gear 68 will be describedbelow), is formed on the outer periphery of the cam barrel 61. The cambarrel 61 is driven and rotated by a drive force transmitted from thedrive gear 68.

Notches 61 b and 61 c (FIG. 19) are provided to the cam barrel 61 in aportion close to the image side along the optical axis A (i.e., in arear portion of the cam barrel 61). In addition, the cam barrel 61 movesback and forth along the optical axis A with a cam effect between thecam groove 62 a of the fixed barrel 62 and the cam pin (not illustrated)of the cam barrel 61. Furthermore, a first-unit cam groove (notillustrated) and a second unit-cam groove (not illustrated) are formedon the inner periphery of the cam barrel 61, which can move back andforth along the optical axis A as described above.

As described above, the notches 61 b and 61 c (FIG. 19) are provided tothe cam barrel 61 in the portion close to the image side along theoptical axis A (i.e., in the rear portion of the cam barrel 61).Accordingly, when the cam barrel 61 moves towards the image plane sidealong the optical axis A (i.e., when the cam barrel 61 moves rearwards)from the wide-angle end illustrated in FIG. 1, the guide shafts 86 and87 enter into the notches 61 a and 61 b, respectively. With theabove-described configuration, the cam barrel 61 can move to the sinkposition illustrated in FIGS. 8 and 19 without any interference betweenthe guide shafts 86 and 87, and the cam barrel 61.

The advancement guide barrel 63 is provided on the inner periphery ofthe cam barrel 61, and can move in the direction of the optical axis Aintegrally with the cam barrel 61. Notches 63 a and 63 b (FIG. 19) areprovided to the advancement guide barrel 63, which is an advancementguide member, in the portion close to the image side along the opticalaxis A (i.e., in the rear portion of the advancement guide barrel 63).

When the advancement guide barrel 63 moves towards the image plane sidealong the optical axis A (i.e., when the advancement guide barrel 63moves rearwards) from the wide-angle end illustrated in FIG. 1, theguide shafts 86 and 87 enter into the notches 63 a and 63 b,respectively. With the above-described configuration, the advancementguide barrel 63 can move to the sink position illustrated in FIGS. 8 and19 without any interference between the guide shafts 86 and 87 and theadvancement guide barrel 63.

The first lens unit 10 is provided between the cam barrel 61 and theadvancement guide barrel 63. A cam pin, which is provided on an outerperiphery of the first lens unit barrel 11 of the first lens unit 10,cam-engages the first-unit cam groove (not illustrated) of the cambarrel 61. In addition, an advancement groove (not illustrated), whichextends along the optical axis A, is formed on the outer periphery ofthe advancement guide barrel 63. Furthermore, the first lens unit barrel11 engages the advancement guide barrel 63 by a protruded portionthereof, which is provided on the inner periphery of the first lens unitbarrel 11 and which enters the advancement groove of the advancementguide barrel 63. With this configuration, a rotation of the first lensunit barrel 11 around the optical axis A is regulated.

The second lens unit 20 is provided on the inner periphery of theadvancement guide barrel 63. In addition, the second lens unit 20,similarly to the first lens unit 10, cam-engages the cam barrel 61 by acam pin (not illustrated), which is provided to the second-unit lensbarrel 21 and which enters the second-unit cam groove (not illustrated)of the cam barrel 61. In addition, a through groove (not illustrated) isprovided to the advancement guide barrel 63 in the direction of theoptical axis A. An engagement portion, which is provided at a basalportion of the cam pin of the second-unit lens barrel 21, engages andenters the through hole of the advancement guide barrel 63. In thismanner, the movement of the second-unit lens barrel 21 in a rotationdirection thereof is regulated.

When the cam barrel 61 rotates, the first lens unit barrel 11 moves backand forth along the optical axis in relation to the cam barrel 61 withthe protruded portion of the first lens unit barrel 11 sliding along theadvancement groove of the advancement guide barrel 63 in the directionof the optical axis A. The advancement and retraction of the first lensunit barrel 11 described above is caused by a cam effect between thefirst-unit cam groove of the cam barrel 61 and the cam pin of the firstlens unit barrel 11. Accordingly, when the cam barrel 61 moves back andforth along the optical axis A in relation to the fixed barrel 62, thefirst lens unit barrel 11 moves back and forth along the optical axis Ain relation to the cam barrel 61 and the first-unit lens 1 moves betweenthe storage position and the shooting position. In addition, the secondlens unit 2 moves between the storage position and the shooting positionby a similar movement.

The drive mechanism for the cam barrel 61 and the prism 6 will bedescribed in detail below with reference to FIGS. 10 through 14. FIG. 10is an exploded perspective view of the cam barrel 61 and a part of themechanism for driving the prism 6.

Referring to FIGS. 10 through 14, a SW motor 67 is a drive source formoving the first lens unit 10 and the second lens unit 20 between thesink position and the wide-angle position. A TW motor 53 is a drivesource for moving the first lens unit 10 and the second lens unit 20between the telephoto end and the wide-angle end.

Each of the SW motor 67 and the TW motor 53 is provided in the followingmanner. That is, a motor axis of each motor is oriented towards theoptical axis B and a motor shaft of each motor is oriented inwards in adirection of the diameter of the cam barrel 61. In addition, the TWmotor 53 is arranged closer to an object side than the SW motor 67 is. Aworm gear 52 is press-fit around the motor shaft of the SW motor 67. Inaddition, a worm gear 54 is press-fit around the motor shaft of the TWmotor 53.

A zoom ring gear 55, a zoom carrier gear 56, and a sun gear 57 areprovided on the same axis and in parallel to the optical axis A in thisorder from the object side (from the upper portion of FIG. 10) betweenthe worm gear 52 and the worm gear 54.

The sun gear 57 includes sun gears 57 a through 57 c, which isconstituted by flat gears of three steps. A gear 66 b, which engages thesun gear 57 a, further engages the worm gear 52 via a helical gear 66 a.

The zoom carrier gear 56 includes a gear 56 a and three shafts, whichare provided on a surface of the gear 56 a facing the object side withsubstantially even intervals in the circumferential direction. A zoomplanet gear 58 is pivoted by each of the three shafts. In addition, theworm gear 54 engages a flat gear 65 a via a helical gear 65 b. The zoomplanet gear 58 engages a gear 57 b. The zoom ring gear 55 includes aninternal gear 55 a and an external gear 55 b. The zoom planet gear 58engages the internal gear 55 a. The external gear 55 b engages the drivegear 68 via an idler gear 59. Furthermore, the drive gear 68 engages thegear 61 a of the cam barrel 61.

A prism drive unit 80 will be described in detail below. The prism driveunit 80 is provided below the sun gear 57. Furthermore, the prism driveunit 80 includes, in order from the object side, a prism carrier 81, atorsion spring 84, and a prism delay gear 82. The prism carrier 81, thetorsion spring 84, and prism delay gear 82 are provided on the same axisas the axis of the sun gear 57. The prism delay gear 82 is rotatablypivoted by the prism carrier 81.

Three shafts are provided on the surface of the prism carrier 81 facingthe object side in the circumferential direction with substantially evenintervals. A prism planet gear 83 is pivoted by each of the threeshafts. The prism planet gear 83 engages a sun gear 57 c and an internalgear fixedly provided on a gear ground plate (not illustrated).

A prism drive gear 85 engages a gear of the prism delay gear 82. Latches81 b and 82 b, which extend in a mutually opposing direction, areprovided to the prism carrier 81 and the prism delay gear 82,respectively. The latch 81 b is provided at a position more to theinside of the latch 82 b in the diameter direction (FIG. 13A).

The torsion spring 84 includes a coil and two arms 84 a and 84 b. Thearms 84 a and 84 b extend from both ends of the coil externally in thediameter direction. The two arms 84 a and 84 b are latched with thelatches 82 b and 81 b of the prism delay gear 82 and the prism carrier81. During assembly, the two arms 84 a and 84 b of the torsion spring 84are precharged by being latched at the latch 82 b in a state in whichthe latches 82 b and 81 b are provided at the same phase (FIG. 13B).

In this state, when the prism delay gear 82 is allowed to freely rotateto rotate the prism carrier 81, the prism carrier 81, the prism delaygear 82, and the torsion spring 84 integrally rotate. On the other hand,when the prism carrier 81 is rotated in a state in which the rotation ofthe prism delay gear 82 is regulated, only the prism carrier 81 rotateswhile the torsion spring 84 is overcharged.

FIG. 11 is a plan view illustrating the holding member 60 configured tohold the prism 6 and a part of the prism drive unit 80.

Referring to FIG. 11, engaging portions 60 a and 60 b are formed on theholding member 60. The engaging portions 60 a and 60 b movably engagethe two guide shafts 86 and 87, which are guide members provided inparallel to each other and extending in the direction of the opticalaxis B. A rack gear 60 c is formed on the engaging portion 60 a. Therack gear 60 c engages the prism drive gear 85. Accordingly, when theprism drive gear 85 rotates, the holding member 60 moves back and forthalong the optical axis B integrally with the prism 6.

When viewed from the object side of the optical axis A, the guide shafts86 and 87, with which the holding member 60 engages, extend into the cambarrel 61 and the advancement guide barrel 63. The guide shafts 86 and87 are configured as described above because it is necessary for theprism 6 to exert a function for bending light from the object from theoptical axis A towards the optical axis B in a shooting mode.

Returning to FIG. 10, operations of the cam barrel 61 and the prism 6will be described in detail.

When the SW motor 67 is driven and the TW motor 53 is stopped, a driveforce is transmitted from the SW motor 67 to the sun gear 57.Accordingly, the sun gear 57 rotates in this state but the zoom carriergear 56, which is connected to the TW motor 53, is stopped. Therefore,the zoom planet gear 58 only rotates without revolving.

For example, if the gear 57 b has nine teeth, the zoom planet gear 58has ten teeth, and the internal gear 55 a of the zoom ring gear 55 hasthirty teeth, then the speed of rotation of the sun gear 57 is decreasedto 1/3.33 of the original speed. This rotational force is transmitted tothe zoom ring gear 55. Accordingly, the rotation of the external gear 55b is transmitted to the drive gear 68 via the idler gear 59. Inaddition, the rotation of the drive gear 68 is transmitted to the gear61 a of the cam barrel 61. In this manner, the cam barrel 61 is drivenand rotated.

The zoom ring gear 55 rotates in a reverse direction of the rotation ofthe sun gear 57. In addition, the rotation of the sun gear 57 istransmitted to the prism carrier 81 via the prism planet gear 83. If theholding member 60 can move in the direction of the optical axis B, thetorsion spring 84 and the prism delay gear 82 rotate integrally with theprism carrier 81, and the holding member 60 moves back and forth in thedirection of the optical axis B. On the other hand, if the movement ofthe holding member 60 in the direction of the optical axis B isregulated, the prism delay gear 82 cannot rotate. Accordingly, thetorsion spring 84 absorbs the rotation of the prism carrier 81 whilebeing overcharged.

When the SW motor 67 is stopped and the TW motor 53 is driven, the sungear 57, which is connected to the SW motor 67, stops. On the otherhand, the zoom carrier gear 56, which is connected to the TW motor 53,rotates. Accordingly, the zoom planet gear 58 revolves while rotating.

For example, if the gear 57 b has nine teeth, the zoom planet gear 58has ten teeth, and the internal gear 55 a of the zoom ring gear 55 hasthirty teeth, then the speed of rotation of the sun gear 57 is increasedby 30%. This rotational force is transmitted to the zoom ring gear 55.In this manner, the cam barrel 61 is driven and rotated.

In this case, the rotation direction of the zoom ring gear 55 is thesame as the rotation direction of the zoom carrier gear 56. In addition,because the sun gear 57 is stopped in this case, the prism carrier 81 isalso stopped. Therefore, no drive force is transmitted to the holdingmember 60.

When the SW motor 67 and the TW motor 53 are driven at the same time, acombined number of rotations (revolutions per minute (rpm)) istransmitted to the zoom ring gear 55. For example, suppose that the sungear 57 is rotated at 1 rpm in the clockwise (CW) direction and that thezoom carrier gear 56 is rotated at 1 rpm in the CW direction. In thiscase, the number of rotations that should be transmitted from the sungear 57 to the zoom ring gear 55 is 0.3 rpm in the counterclockwise(CCW) direction. Furthermore, in this case, the number of rotations thatshould be transmitted from the zoom carrier gear 56 to the zoom ringgear 55 is 1.3 rpm in the CW direction. Therefore, as a result ofcombining the above-described number of rotations together, the zoomring gear 55 rotates at 1 rpm in the CW direction.

Suppose that the sun gear 57 is rotated at 1.3 rpm in the CW directionand that the zoom carrier gear 56 is rotated at 0.3 rpm in the CWdirection. In this case, the number of rotations that should betransmitted from the sun gear 57 to the zoom ring gear 55 is 0.39 rpm inthe CCW direction. Furthermore, in this case, the number of rotationsthat should be transmitted from the zoom carrier gear 56 to the zoomring gear 55 is 0.39 rpm in the CW direction. Therefore, as a result ofcombining the above-described number of rotations together, the zoomring gear 55 stops.

As described above, it can be understood that by appropriately selectingand setting the number of rotations and the direction of rotation of theSW motor 67 and the TW motor 53, the prism 6 can be driven when the cambarrel 61 is stopped. In addition, it can also be understood that aspeed decreasing ratio of the array of gears connected to the SW motor67 becomes high while the speed decreasing ratio of the array of gearsconnected to the TW motor 53 becomes low. The speed decreasing ratioswill be described in detail later.

An operation for moving the prism 6 to the shooting position byadvancing and moving the first lens unit 10 and the second lens unit 20in the direction of the optical axis A will be described in detail belowwith reference to FIGS. 12 and 13A through 13C.

FIG. 12 is an expansion view of the fixed barrel 62 viewed from an innerperiphery thereof. Referring to FIG. 12, in the inner peripheral portionof the fixed barrel 62, the cam grooves 62 a (FIG. 6) are provided at aplurality of positions in a circumferential direction with substantiallyeven intervals. More specifically, the cam grooves 62 a are providedalong the outer periphery of the cam barrel 61 and a cam pin (notillustrated) cam-engages the cam groove 62 a. In addition, a notch 62 bis formed on a rear edge of the fixed barrel 62. The holding member 60,which holds the prism 6, comes through the notch 62 b when the holdingmember 60 moves back and forth in the direction of the optical axis B.

In addition, clearance grooves (see FIG. 19) for preventing aninterference between the cam barrel 61 and the advancement guide barrel63, and the guide shafts 86 and 87, which may otherwise occur when thecam barrel 61 and the advancement guide barrel 63 retract to the sinkposition (retraction position) along the optical axis A, are formed atportions of the cam barrel 61 and the advancement guide barrel 63corresponding to the guide shafts 86 and 87. The clearance grooves areprovided because in order to move the prism 6 to the shooting position,the guide shafts 86 and 87, with which the holding member 60 engages,are extended into the cam barrel 61 and the advancement guide barrel 63when viewed from the object side of the optical axis A.

Accordingly, even if the guide shafts 86 and 87, with which the holdingmember 60 engages, extend into the cam barrel 61 and the advancementguide barrel 63 when viewed from the object side of the optical axis A,the length of the lens barrel in the storage state (retraction state) inthe direction of the optical axis A can be shortened because of thenotches 61 a and 61 b, and 63 a and 63 b, which function as theclearance grooves.

The cam barrel 61 and the advancement guide barrel 63 correspond to adrive barrel of the present invention.

FIGS. 13A through 13C illustrate a phase relationship between the prismcarrier 81 and the prism delay gear 82, and an amount of charge appliedto the torsion spring 84.

When the lens barrel is positioned at the sink position, the cam pin ofthe cam barrel 61 is positioned at a position 62 c in FIG. 12 within thecam groove 62 a of the fixed barrel 62. In this state, the prism carrier81 and the prism delay gear 82 are in the phase relation in which thetorsion spring 84 is overcharged as illustrated in FIG. 13A. In thisstate, the holding member 60 is pressed by the charging force from thetorsion spring 84 towards the retraction direction along the opticalaxis B (i.e., towards the image sensor 8). Furthermore, the movement ofthe holding member 60 in the retraction direction is regulated by amechanical end (not illustrated).

To set the lens barrel to the shooting mode (state), at first, the SWmotor 67 is rotated in the direction of advancement of the cam barrel61. In this state, the cam pin of the cam barrel 61 moves in and alongthe cam groove 62 a of the fixed barrel 62 rightwards in FIG. 2. Inaddition, the first lens unit 10 and the second lens unit 20 move alongthe optical axis A in the direction of advancement in a segment in whicha lift is provided. During the advancement operation, the prism carrier81 also rotates in the direction of advancement of the holding member 60to the shooting position. In this state, because the torsion spring 84is being overcharged, the prism delay gear 82 remains being stopped.Therefore, the holding member 60 does not move from the retractionposition.

When the cam barrel 61 has advanced in the direction of the optical axisA and a space into which the holding member 60 can move towards theshooting position is formed, the phase of the latch 81 b of the prismcarrier 81 and the latch 82 b of the prism delay gear 82 match eachother as illustrated in FIG. 13B.

When the SW motor 67 is rotated in the direction of advancement of thecam barrel 61, the cam pin of the cam barrel 61 moves in and along thecam groove 62 a of the fixed barrel 62 rightwards in FIG. 12. At thesame time, the holding member 60 moves to the shooting position.

When the cam barrel 61 reaches the wide-angle end, the TW motor 53 isdriven in the direction of retraction of the cam barrel 61 in a state inwhich the SW motor 67 is driven in the direction of advancement of thecam barrel 61. Accordingly, only the holding member 60 continues movingtowards the shooting position in the direction of the optical axis Bwhen the cam barrel 61 is stopped at the wide-angle end.

When the holding member 60 reaches the shooting position, the holdingmember 60 contacts a shooting side stopper (not illustrated) and stopsthere. The prism delay gear 82 stops at the same time as the holdingmember 60 stops. In this case, by further continuing the driving of theSW motor 67 in the direction of advancement of the cam barrel 61, theprism carrier 81 continues to cause the holding member 60 to rotate inthe direction of the shooting position and overcharges the torsionspring 84.

By overcharging the torsion spring 84 with an appropriate force, theholding member 60 is pressed against the shooting side stopper (notillustrated) by the effect of the torsion spring 84. Accordingly, theposition and the attitude of the holding member 60 can be stabilizedduring shooting.

When the torsion spring 84 is overcharged to a predetermined overchargestate, the SW motor 67 and the TW motor 53 are stopped.

By executing the above-described operation, the first lens unit 10, thesecond lens unit 20, and the prism 6 are moved to the wide-angle end. Inthis state, the operation state of the lens barrel becomes the shootingstate. When the cam barrel 61 reaches the wide-angle end, the cam pinmoves to a position 62 d in the cam groove 62 a of the fixed barrel 62.Subsequently, the third lens unit 30 and the fourth lens unit 40 aremoved to a predetermined position along the optical axis B.

By executing the above-described operations in reversed order, the lensbarrel can be moved from the wide-angle end to the SINK position. Morespecifically, at first, the third lens unit 30 and the fourth lens unit40 are retracted towards the image sensor 8 along the optical axis B.Then, while driving the TW motor 53 in the advancement direction of thecam barrel 61, the SW motor 67 is driven in the direction of retractionof the cam barrel 61 at the same time. In this state, the cam barrel 61does not rotate but only the prism carrier 81 rotates in the directionof advancement of the holding member 60 to the shooting position.

In addition, the prism carrier 81 rotates by an amount equivalent to theovercharge of the torsion spring 84. Accordingly, the phase of the latch81 b of the prism carrier 81 and the latch 82 b of the prism delay gear82 match each other. In this state, the prism delay gear 82 rotates inthe direction of retraction of the holding member 60 to the retractionposition integrally with the prism carrier 81 and the torsion spring 84.Accordingly, the holding member 60 moves in the retraction direction.

After the holding member 60 has moved to the retraction position and astorage space is formed in a portion to the rear of the cam barrel 61,the TW motor 53 stops and only the SW motor 67 continues driving in thedirection of retraction of the cam barrel 61. Accordingly, the cambarrel 61 starts its retraction. When the holding member 60 reaches theretraction position, the holding member 60 contacts a retraction sidemechanical end (not illustrated) and stops there. The prism delay gear82 stops at the same time.

The SW motor 67 continues driving until the cam barrel 61 is retractedto the storage position. Accordingly, the prism carrier 81, whileovercharging the torsion spring 84, continues to rotate the holdingmember 60 in the direction of retraction thereof. After the cam barrel61 reaches and is stored at the sink position and the first lens unit 10and the second lens unit 20 are stored, the SW motor 67 stops.

In executing a variable magnification operation by moving the lensbarrel between the wide-angle end and the telephoto end, the first lensunit 10 and the second lens unit 20 can be moved in the direction ofoptical axis A without moving the holding member 60 in the direction ofthe optical axis B by driving the TW motor 53 only. When the lens barrelis positioned at the telephoto end, the cam pin of the cam barrel 61 ispositioned at a position 62 e in the cam groove 62 a of the fixed barrel62 (see FIG. 12).

Now, an effect of the above-described configuration, in which the speeddecreasing ratio of the array of gears connected to the SW motor 67 ishigh and the speed decreasing ratio of the array of gears connected tothe TW motor 53 is low, will be described in detail below.

In general, the load of driving the cam barrel 61 is higher in a regionfrom the sink position to a shooting region, whose lift angle of the camgroove 62 a of the fixed barrel 62 is high, than in a shooting regionfrom the wide-angle end to the telephoto end. In the region from thesink position to the shooting region, a further load of operating a lensbarrier may often be applied. Accordingly, it is necessary to increase atorque of the motor by using the gear array whose speed decreasing ratiois high.

On the other hand, for the shooting range from the wide-angle end to thetelephoto end, it is necessary to keep the number of rotations of themotor low to prevent undesired recording of the noise generated bydriving the lens during shooting of a moving image. In this case, if agear array having a high speed decreasing ratio is used, the rotationspeed of the cam barrel may become extremely low.

In the present exemplary embodiment, in the region from the sinkposition to the shooting range, in which the load of the cam barrel 61is high, the cam barrel 61 is driven by transmitting the drive forcefrom the SW motor 67 to the cam barrel 61 via the gear array having ahigh speed decreasing ratio. On the other hand, in the shooting rangefrom the wide-angle end to the telephoto end, the cam barrel 61 isdriven by transmitting the drive force from the TW motor 53 to the cambarrel 61 via the gear array having a low speed decreasing ratio to thecam barrel 61. Accordingly, even if the TW motor 53 is rotated at a lowspeed to maintain a low noise-state while driving the motor duringshooting of a moving image, the variable magnification operation can beexecuted at an appropriate operation speed.

In the present exemplary embodiment, different types of motors can beused for the SW motor 67 and the TW motor 53. For example, a directcurrent (DC) motor can be used as the SW motor 67, and a stepping motorcan be used as the TW motor 53. In general, a stepping motor can be morestably controlled at a low speed compared with a DC motor. Therefore, astepping motor can be used when the motor is driven at a low speedduring a moving image shooting operation.

In addition, for a method for driving the stepping motor, a microstepdrive method or a two-phase excitation drive method can be selected andused. If the microstep drive method is used, the motor can be driven ata more highly silent operation state. On the other hand, if thetwo-phase drive method is used, the motor can be driven with a highertorque. Accordingly, the method can be selectively used. Morespecifically, the microstep drive method can be used for changing themagnification in shooting a moving image, in which it is necessary tomaintain a sufficient level of silence. On the other hand, the two-phasedrive method can be used for changing the magnification in shooting astill image.

With the configuration of the array of gears of the drive mechanismaccording to the present exemplary embodiment, the cam barrel 61 can bedriven regardless of which of the SW motor 67 and the TW motor 53 isdriven in all the region from the sink position to the telephoto end.Therefore, the drive method can be selectively used in the followingmanner. That is, if it is necessary to change the magnification at ahigh speed, the SW motor 67 is used. On the other hand, if it isnecessary to execute variable magnification at a low speed, the TW motor53 is used.

Returning to FIG. 10, the pulse gear array 70 will be described indetail below, which is configured to detect the position of the firstlens unit 10 and the second lens unit 20 in the direction of the opticalaxis A.

Referring to FIG. 10, the pulse gear array 70 is connected to the zoomring gear 55 and the idler gear 59, which are output gears of a planetgear array. A plurality of blades is provided to a pulse board 71 of alast stage of the pulse gear array 70. A photo-interrupter 72 counts thenumber of times of passage of the plurality of blades. In this manner,the amount of rotation of the cam barrel 61 is detected. The speedincreasing ratio of the pulse gear array 70 and the number of blades ofthe pulse board 71 are determined at the ratio and the number with whicha necessarily high resolution, which is set according to an opticaldesign, can be achieved.

Essentially, if a gear array is used to transmit a drive force from amotor, the amount of rotation of a cam barrel is linearly determinedaccording to the speed decreasing ration in relation to the rotationamount of the motor because the loss of rotation amount, which mayotherwise arise due to sliding, may not arise. However, in an actualoperation, the amount of rotation of the cam barrel may vary and becomeuneven in relation to the rotation amount of the motor due to a backlashor an engagement error of the gears.

However, in a conventional lens barrel, in which one motor drives onecam barrel, the engagement relationship among the gears may not varywhen the motor is driven once the gear array is assembled. Morespecifically, because the same pairs of gears engage in every rotation,the state of variation of the rotation amount of the cam barrel inrelation to the motor rotation amount is the same for every rotation.Therefore, if the amount of rotation of the cam barrel is calculatedaccording to the motor rotation amount, the calculated cam barrelrotation amount has only a small amount of error from the actual cambarrel rotation amount.

On the other hand, if one cam barrel is driven by utilizing therotational force generated by combining the rotational forces equivalentto the amounts of rotation of the two motors, which is achieved by usingthe planet gear array, as in the present exemplary embodiment, when onemotor is rotated, the relationship between the teeth of the other motorand teeth of the zoom ring gear 55 may vary.

In other words, because the gear engages with a different gear everytime the camera is powered on, the state of variation of the cam barrelrotation amount in relation to the motor rotation amount may bedifferent each time the camera is powered on. Accordingly, even if thecam barrel rotation amount is calculated according to the motor rotationamount, the error of the calculated cam barrel rotation amount withrespect to the actual cam barrel rotation amount may become large.

However, in the present exemplary embodiment, the pulse gear array 70 isbranched from the idler gear 59, which is provided between the zoom ringgear 55 and the cam barrel 61, which are output gears of the planet geararray. Accordingly, the engagement relationship between the teeth of thegears of the pulse gear array 70 and the cam barrel 61 is invariant.Accordingly, the present exemplary embodiment can detect the amount ofrotation of the cam barrel with an error whose level is as low as thatof a conventional lens barrel.

As described above, in the present exemplary embodiment, the throughhole 64 a is formed on the back surface wall of the zoom body 64.Accordingly, the space corresponding to the dimension Y of the throughhole 64 a (a space that is at least larger than a space corresponding tothe dimension X) is included in the retraction space formed in theportion to the rear of the first lens unit 10 and the second lens unit20.

In addition, in the present exemplary embodiment, the notches (FIG. 19),which are the clearance grooves for preventing an interference of thesecond-unit lens barrel 21, the cam barrel 61, and the advancement guidebarrel 63 with the guide shafts 86 and 87, which may otherwise occurwhen the first lens unit 10 and the second lens unit 20 retract alongthe optical axis A, are provided to the second-unit lens barrel 21, thecam barrel 61, and the advancement guide barrel 63. The notches (i.e.,the notches 61 a and 61 b and 63 a and 63 b) are provided at portions ofthe second-unit lens barrel 21, the cam barrel 61, and the advancementguide barrel 63 corresponding to the guide shafts 86 and 87 in thestorage state (the retraction state).

Accordingly, the space into which the first lens unit 10 and the secondlens unit 20, which are provided along the optical axis (thelight-incidence optical axis) A, are to be retracted can be enlarged. Asa result, the thickness of the digital camera in the lens barrelretracted state can be further reduced.

Now, positions of a drive unit configured to drive the first lens unit10, the second lens unit 20, the third lens unit 30, the fourth lensunit 40, and the fifth lens unit 50 relative to the microphone will bedescribed in detail below.

FIG. 17 is a perspective view of a lens barrel positioned at the sinkposition (storage position) viewed from an object side of the first lensunit included in a camera body 100 when viewed from the direction of theoptical axis. FIG. 20 is a cross section of the camera body 100sectioned in a direction normal to the optical axis of the first lensunit in a state in which the lens barrel is positioned at the sinkposition (storage position). Referring to FIG. 17, the digital cameraincludes a lens barrel 101, a release switch 102, a flash unit 103, anda stereo microphone 104. The stereo microphone is constituted by a leftchannel microphone 104L and a right channel microphone 104R.

FIG. 20 is a cross section of the imaging apparatus sectioned in adirection normal to the optical axis of the first lens unit in a statein which the lens barrel is positioned at the sink position (storageposition).

Referring to FIG. 20, the imaging apparatus includes a battery 105, atripod installation screw 106, a main capacitor 107, a connecterterminal 108 for connecting thereof to an apparatus external to thecamera, and an operation substrate 109, which electrically connects therelease switch 102. In addition, the imaging apparatus includes a zoomdrive unit 110, which is configured to drive the TW motor 53, the geararray from the worm gears 52 and 54 to the drive gear 68, the steppingmotor 32, the gear 33, the gear 34, and the stepping motor 42 duringchanging of the magnification and focusing to drive the first lens unit10, the second lens unit 20, the third lens unit 30, the fourth lensunit 40, and the fifth lens unit 50 in the direction of the opticalaxis. The zoom drive unit 110 may become a source of noises, which maybe unintentionally recorded when each lens unit is moved during shootingof a moving image.

In the example illustrated in FIG. 20, the left channel microphone 104Land the zoom drive unit 110 are distant from each other by a distance L.Furthermore, the right channel microphone 104R and the zoom drive unit110 are distant from each other by a distance R.

As illustrated in FIG. 20, the left channel microphone 104L and theright channel microphone 104R of the microphone 104 are provided acrossthe optical axis B relative to the zoom drive unit 110 and substantiallyin parallel to the optical axis B. Accordingly, the above-describedcomponents of the digital camera are arranged so as to maintain thedistance L between the zoom drive unit 110, which is the noise source,and the left channel microphone 104L, and the distance R between thezoom drive unit 110 and the right channel microphone 104R to be large,and so as to prevent the distances L and R from greatly differing fromeach other.

Accordingly, the level of noises from the zoom drive unit 110, which maybe unintentionally recorded during a magnification changing operationand a focusing operation in shooting a moving image can be decreased. Inaddition, the levels of the noises in the left and the right channelsmay not be greatly differ from each other. As a result, it becomesunnecessary to execute electrical noise reduction processing unevenly tothe left and the right channels. Accordingly, a user of the camera maynot feel uncomfortable about the difference between the sound from theleft and the right channels during reproduction of recorded data.

In addition, as illustrated in FIG. 20, the zoom drive unit 110 isprovided between the optical axis B and a bottom surface of the camerabody 100, in which state the motors are arranged along the optical axisB. A main capacitor 107 is arranged along the optical axis B at aposition opposite to the zoom drive unit 110 across the optical axis B.By arranging longitudinal parts (members), such as the zoom drive unit110 and the main capacitor 107, across the optical axis B, the spacescan be effectively utilized. As a result, the size of the camera body100 can be effectively reduced.

A method for installing the image sensor 8 will be described in detailbelow with reference to FIG. 18 and FIGS. 20 through 24. FIG. 18 is aperspective view of the camera body 100 viewed from the direction of theoptical axis of the first lens unit. FIG. 21 is a cross section of thecamera body 100 when the lens barrel is positioned at the sink position(storage position). FIG. 22 is a perspective view of the image sensor 8included in the camera body 100 viewed from the opposite side of theobject along the optical axis B. FIG. 23 is a perspective view of theimage sensor viewed from the object side along the optical axis B. FIG.24 is an exploded perspective view of the image sensor 8, a sensor plate200, and an imaging substrate 201, which are to be installed to the lensbarrel.

Referring to FIG. 18, a user can select a function of the camera byoperating an operation unit 204. The user can view an image to becaptured on a liquid crystal display (LCD) panel 205. Referring to FIGS.20 through 24, the sensor plate 200 is an image sensor holding memberconfigured to hold the image sensor 8. An imaging substrate 201 includesimage processing circuits 201 a and 201 b, which are mounted thereon.The imaging substrate 201 processes an image signal output from theimage sensor 8 by using the image processing circuits 201 a and 201 b.An adhesive 202 is used to bond the image sensor 8. In addition, aplurality of fixation screws 203 is provided to fix the sensor plate 200to the zoom body 64.

Referring to FIGS. 21 through 24, the sensor plate 200 is constituted bya holding portion 200 a and a connection portion 200 b. The holdingportion 200 a has a surface substantially the same level as the surfaceof the image sensor 8 at the rear of the optical axis B. The connectionportion 200 b extends from the holding portion 200 a. More specifically,the connection portion 200 b extends from the image plane side along theoptical axis B in a direction away from the object side.

The adhesive 202 is applied to a gap among three sides of a surface ofthe image sensor 8 that is perpendicular to the optical axis B and theholding portion 200 a to fix the image sensor 8 onto the sensor plate200.

The connection portion 200 b and the image sensor 8 connect a U-shapedholding portion 200 a around the imaging substrate 201 in the directionof the optical axis B. By connecting the holding portion 200 a by usingthe connection portion 200 b, the accuracy of parts of the sensor plate200 can be improved. In addition, the interference between the sensorplate 200 and the operation unit 204 can be prevented. As a result, thethickness of the camera body 100 in the direction of the optical axis Acan be effectively reduced.

As described above, in the present exemplary embodiment, the notches 61b, 61 c, 63 a, and 63 b are provided to the cam barrel 61 and theadvancement guide barrel 63. With the above-described configuration, thecam barrel 61 and the advancement guide barrel 63 can retract from theguide shafts 86 and 87 towards the image plane along the optical axis A.

The configuration of the present invention is not limited to theabove-described exemplary embodiment. More specifically, a material ofeach component, the shape, the dimension, the type, the number, and theinstallation location of each component can be appropriately changed ormodified within the scope of the present invention.

In addition, in the above-described exemplary embodiment, the prism 6 isdescribed as an example of the reflection optical element. However, thepresent invention is not limited to this. More specifically, a differentoptical member, such as a mirror, can be used as the reflection opticalelement.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all modifications, equivalent structures, and functions.

This application claims priority from Japanese Patent Application No.2010-183271 filed Aug. 18, 2010, which is hereby incorporated byreference herein in its entirety.

What is claimed is:
 1. An optical apparatus comprising: a cam barrelconfigured to hold an optical member, which is movable back and forthalong a first optical axis, on an inner periphery of the cam barrel; areflection member configured to bend a light flux from an object fromthe first optical axis towards a second optical axis which extends in adifferent direction to a first optical axis; and a guiding memberextending in a direction parallel with the second optical axis andconfigured to support and hold the reflection member to be movable backand forth in the direction parallel with the second optical axis,wherein the guiding member is configured to enter into a notch providedto the cam barrel when the optical member is stored into a space alongthe first optical axis into which the reflection member has retracted.2. The optical apparatus according to claim 1, wherein the notch isprovided at a rear portion of the first optical axis.
 3. An opticalapparatus comprising: an optical member configured to be movable backand forth along a first optical axis; an advancement guide memberconfigured to regulate a rotation of the optical member around the firstoptical axis of the optical member; a reflection member configured tobend a light flux from an object from the first optical axis towards asecond optical axis which extends in a different direction to a firstoptical axis; and a guiding member extending in a direction parallelwith the second optical axis and configured to support and hold thereflection member to be movable back and forth in the direction parallelwith the second optical axis, wherein the guiding member is configuredto enter into a notch, which is provided to the advancement guidemember, when the optical member is stored into a space along the firstoptical axis into which the reflection member has retracted.
 4. Theoptical apparatus according to claim 3, wherein the notch is provided ata rear portion of the first optical axis.